To find the origin of Halloween, you have to look to the festival of Samhain in Ireland's Celtic past.
Samhain had three distinct elements. Firstly, it was an important fire festival, celebrated over the evening of 31 October and throughout the following day.
The flames of old fires had to be extinguished and ceremonially re-lit by druids.
It was also a festival not unlike the modern New Year's Day in that it carried the notion of casting out the old and moving into the new.
To our pagan ancestors it marked the end of the pastoral cycle – a time when all the crops would have been gathered and placed in storage for the long winter ahead and when livestock would be brought in from the fields and selected for slaughter or breeding.
But it was also, as the last day of the year, the time when the souls of the departed would return to their former homes and when potentially malevolent spirits were released from the Otherworld and were visible to mankind.
The Celts celebrated four major festivals each year. None of them was connected in anyway to the sun's cycle. The origin of Halloween lies in the Celt's Autumn festival which was held on the first day of the 11th month, the month known as November in English but as Samhain in Irish.
The festivals are known by other names in other Celtic countries but there is usually some similarity, if only in the translation.
In Scottish Gaelic, the autumn festival is called Samhuinn. In Manx it is Sauin.
The root of the word – sam – means summer, while fuin means end. And this signals the idea of a seasonal change rather than a notion of worship or ritual.
The other group of Celtic languages (known as Q-Celtic) have very different words but a similar intention. In Welsh, the day is Calan Gaeaf, which means the first day of winter. In Brittany, the day is Kala Goanv, which means the beginning of November.
The Celts believed that the passage of a day began with darkness and progressed into the light. The same notion explains why Winter – the season of long, dark nights – marked the beginning of the year and progressed into the lighter days of Spring, Summer and Autumn.
So the 1st of November, Samhain, was the Celtic New Year, and the celebrations began at sunset of the day before ie its Eve.
Harvest was celebrated by the Romans with a festival dedicated to Pomona, the goddess of the fruits of the tree, especially apples. The origin of Halloween's special menus, which usually involve apples (as do many party games), probably dates from this period.
Pomona continued to be celebrated long after the arrival of Christianity in Roman Europe. So, too, did Samhain in Ireland and it was inevitable that an alternative would be found to push pagan culture and lore into a more 'acceptable' Christian event.
Sure enough, the 7th-century Pope Boniface, attempting to lead his flock away from pagan celebrations and rituals, declared 1st November to be All Saints Day, also known as All Hallows Day.
The evening before became known as Hallows' Eve, and from there the origin of Halloween, as a word, is clear.
For Celts, Samhain was a spiritual time, but with a lot of confusion thrown into the mix.
Being 'between years' or 'in transition', the usually fairly stable boundaries between the Otherworld and the human world became less secure so that puka, banshees, fairies and other spirits could come and go quite freely. There were also 'shape shifters' at large. This is where the dark side of Halloween originated.
To ward off the evil let loose at Samhain, huge bonfires were lit and people wore ugly masks and disguises to confuse the spirits and stop the dead identifying individuals who they had disliked during their own lifetime.
They also deliberately made a lot of noise to unsettle the spirits and drive them away from their homes. The timid, however, would leave out food in their homes, or at the nearest hawthorn or whitethorn bush (where fairies were known to live), hoping that their generosity would appease the spirits.
For some, the tradition of leaving food (and a spoon to eat it!) in the home – usually a plate of champ or Colcannon – was more about offering hospitality to their own ancestors.
Just as spells and incantations of witches were especially powerful at Samhain, so the night was believed to be full of portents of the future.
While the origin of Halloween doesn't lie specifically in Derry, the world's biggest Halloween party is held in that city every year. More than 30,000 people take to the streets, most of them dressed as witches, ghouls, vampires and monsters from the Otherworld.
It's a time when you're almost certain to hear the Banshees screaming – assuming you can hear anything much above the marching bands, ceilidh music, hard rock and calypso as the carnival proceeds through the town.
Waterloo Place plays host to a free concert, and many events, including Ghost Walks, are held throughout the city before a spectacular fireworks display brings celebrations to a close.
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